Thursday, January 5, 2012

Avoid ibuprofen if you want to grow muscle?

Well that heading is just to promote some interest, but to be honest it does have something to do with this post. I spotted this bit of research reported yesterday, about how muscles get the signal to grow. Developing and retaining muscle is not just an issue for bodybuilders or athletes, it is essential to health as we grow old.

We take it for granted, but the fact that our muscles grow when we work them makes them rather unique. Now, researchers have identified a key ingredient needed for that bulking up to take place. A factor produced in working muscle fibers apparently tells surrounding muscle stem cell "higher ups" that it's time to multiply and join in, according to a study in the January Cell Metabolism, a Cell Press journal.

The research identifies this factor as "serum response factor (Srf)" which translates the mechanical signal of work into a chemical one.

Srf works through a network of genes, including one known as Cox2. That raises the intriguing possibility that commonly used Cox2 inhibitors—think ibuprofen—might work against muscle growth or recovery, Sotiropoulos notes.

Adult skeletal muscles adapt their fiber size to workload. We show that serum response factor (Srf) is required for satellite cell-mediated hypertrophic muscle growth. Deletion of Srf from myofibers and not satellite cells blunts overload-induced hypertrophy, and impairs satellite cell proliferation and recruitment to pre-existing fibers. We reveal a gene network in which Srf within myofibers modulates interleukin-6 and cyclooxygenase-2/interleukin-4 expressions and therefore exerts a paracrine control of satellite cell functions. In Srf-deleted muscles, in vivo overexpression of interleukin-6 is sufficient to restore satellite cell proliferation but not satellite cell fusion and overall growth. In contrast cyclooxygenase-2/interleukin-4 overexpression rescue satellite cell recruitment and muscle growth without affecting satellite cell proliferation, identifying altered fusion as the limiting cellular event. These findings unravel a role for Srf in the translation of mechanical cues applied to myofibers into paracrine signals, which in turn will modulate satellite cell functions and support muscle growth.

I read somewhere when I was researching about DOMS (delayed onset muscle soreness) that if you are treating an injury with anti-inflammatory drugs you shouldn't take them just before exercise but should take them afterwards. Not sure why but presumably it has something to do with the effects of blocking COX enzymes and the effect that would have on performance?